On Mon, 14 Jan 2002, [iso-8859-1] Kym Bennet wrote:
> Hi all
>
> As an impartial observer, I have been avoiding this
Your comments seem hardly impartial.
> Leg flags are in fact uncontrolled rudders with no
> bearings. On a small bird such as a Red-necked Stint,
> the leg flags have a combined surface area greater
> than 15% of the total surface of the bird. This is
> most significant. Now I don't claim to be an impartial
> aeronautical engineer however one does not need to be
> an intellectual giant to assume that combined with
> their additional weight, attaching numerous large
> uncontrolled rudders to a small flying object would
> have a radical influence on it's control, particularly
> in strong winds.
>
15% is an enormous number. You seem to be saying that a flagged bird has
a fifth greater area(Weight is not an enormous consideration here, you'd
have to admit) than an unflagged bird. In effect, you are saying that the
flag is larger than a sparrow?
> In extreme conditions, the influence of leg flags are
> likely to be catastrophic to the bird, caused from the
> interaction of wind on these uncontrolled rudders as
> the bird attempts to alight, scramble or roost and
> generally maneuver to cover. Obvious? Before my
> critics say that I have no proof that this happens, I
> say there is a growing amount of evidence to show that
> leg flags are detrimental to small birds in strong
> winds, convince us that they are not!
>
We know what good they do, and even under the assumption that they do
some evil, we can see that on the whole, they do more good than evil. For
example, identification of habitat, knowledge of migratory patterns,
and some estimate of wild mortality (even if slightly biased) are very
useful to conservation efforts.
> Correlation? Is there a correlation between leg flags
> and the reported deaths of many Little Terns at Lake
> Tyers on Christmas eve? More than 20% of the dead
> Terns were banded and many more flagged birds are not
> unaccounted for! So the result speaks for itself.
> Where are they now?
>
This in itself is not a statistic that is reliable. What would be is a
proportion of banded birds that die as compared to that of unbanded (or
unflagged) birds over a long enough period of time.
> Where are all these multiple leg flagged Red-necked
> Stints now? An obvious correlation is that the leg
> flagged Stints are missing. Do they have a much
> shortened life span due to their leg flags? Should the
> missing birds be presumed dead?
>
This, in itself is not sufficient to prove a correlation (I am speaking
as someone who has studied statistics upto senior level). For one thing,
the absolute numbers would be required to prove that these are not random
fluctuations. At any rate, no numbers have been provided here.
> How about one of the "pro banders" posting on
> birding-aus, the following information about
> banded/leg flagged Red-necked stints; The date,
> precise number and location of where these birds were
> marked and the colour band/flag id of all birds marked
> since July 1997. This will enable all of us to
> appreciate the extent of the Stint flagging project
> over the last five seasons, and perhaps encourage some
> of us to go looking for the survivors.
>
Since you are of the prosecuting team, I would say that the burden of
proof lies with you.
> Obvious? --- Questions need to be asked about where
> are all the missing leg flagged waders. Why are they
> missing?
>
This has not been proved, at least here.
> Obvious? --- There are none so blind as those who
> cannot see!
Those who cannot see are blind, that is by definition. The actual quote
is "There is none so blind as he who will not see".
Kiran
--------------------------------------------------------------------------
Kiran Krishna
3rd yr physics
(Falkiner High Energy Physics)
University of Sydney
NSW 2006
--------------------------------------------
Liberty is not a means to a higher political end. It is itself the highest
political end.
- Lord Acton
Both liberty abd property are precarious, unless the posessors have sense
and spirit enough to defend them.
- Junius (Philip Francis Jr)
http://www.physics.usyd.edu.au/hienergy
http://www.physics.usyd.edu.au/~kiran
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